Flask with valve



FIG. 1 is right side view showing the new design.

FIG. 2 is a left side view thereof.

FIG. 3 is front view thereof.

FIG. 4 is a back view thereof; and,

FIG. 5 is a top view thereof.

The broken lines are included for the purpose of illustrating the portions of the flask with valve that form no part of the claimed design. 

CLAIM The ornamental design for a flask with valve, as shown and described. 